An electrocautery instrument is a surgical instrument that is used to heat tissue with electricity. Electrocauterization (or electrocautery) is a safe procedure that is routinely used in surgery to remove unwanted or harmful tissue. It can also be used to burn and seal blood vessels, which helps reduce or stop bleeding. A small probe with an electric current running through it is used to burn or destroy the tissue. A grounding pad is placed on the body (usually the thigh) before the surgery to protect the patient from the harmful effects of the electricity.
In U.S. Pat. No. 6,063,081, an electrocautery instrument is described that is configured with a hollow electrode/blade disposed within a retractable suction tube. The suction tube is slidably disposed partially within an internal lumen of a handle and projects distally out of the end thereof. The suction tube is adapted to slide proximally and distally with respect to the handle and electrode/blade by means of a sliding lever extending out of a slot in the handle. With the suction tube in a retracted position, a distal portion of the electrode/blade projects beyond the distal tip of the tube, such that electrocautery can be performed. With the suction tube in an advanced position, the suction tube completely conceals the tip of the electrode/blade. The hollow electrode/blade has a source of conductive fluid coupled to the proximal end thereof. This conductive fluid is expelled from the distal (blade) end of the hollow electrode/blade during electrocautery. The conductive fluid emanating from the electrode/blade conducts the RF electrocautery energy away from the blade so that it is primarily the fluid, rather than the metal blade, which actually accomplishes cutting/cauterisation of the treated tissue.
The disadvantage of this type of electrocautery instruments is that the suction tube has to be moved manually with respect to the handle and the electrode/blade using a handle.
A safety needle is a needle having a protected sharp tip to prevent inadvertent tissue contact.
The oldest and most traditional safety needle was developed in 1932 by Janos Veress and is called a Veress needle. Such a conventional Veress needle comprises an outer, preferably tubular, cannula with a sharp tip or point in order to allow piercing or penetration of the tissue forming the wall of an anatomical structure or an anatomical cavity. The force required to penetrate this wall is dependent upon the type and the thickness of the tissue of this wall. Once this wall has been penetrated, it is desirable to protect this sharp tip of the outer cannula to prevent inadvertent contact with tissue in the anatomical structure or further tissue forming the wall of this anatomical structure or anatomical cavity. Particularly, when a substantial force is needed to pierce through this wall, once this wall has been pierced, a problem could appear in that the sharp tip travels too far into the anatomical structure or cavity because of lack of further tissue resistance causing inadvertent injury of tissue and/or the wall of the same or other anatomical structures or anatomic cavities. Therefore, preferably an inner, preferably tubular, cannula with a blunt tip is provided which is pushed in the shaft of the outer cannula when a direct pressure is exerted on the blunt tip, as when penetrating the wall of the anatomical structure of cavity, and which automatically emerges out of the outer cannula once the wall of the tissue has been pierced. In order to be able to automatically emerge out of the outer cannula, the inner cannula is attached internally to a spring mechanism. Accordingly, when this Veress needle is pushed with its blunt tip against the wall that has to be pierced, the blunt tip retracts allowing the sharp end of the Veress needle to pierce this wall. Once the Veress needle has pierced through this wall, the Veress needle no longer encouters any resistance and the blunt end which is attached to the internal spring re-emerges to protect the anatomical structure from inadvertent puncture.
The safety of this Veress needle consequently is a big advantage thereof. A further big advantage thereof is the inherent physical feedback of the Veress needle, i.e. by hearing and sensing a ‘click’ when the inner cannula emerges out of the outer cannula after that the wall of the anatomical structure or anatomical cavity to be treated has been penetrated, hence informing the surgeon.
Until now however, these Veress needles only have a limited use and can only be applied in one way fluid applications, such as abdominal access techniques for laparoscopy, wherein CO2 is inserted through the Veress needle to inflate the space creating a pneumoperitoneum, and minimal invasive surgery.
Other examples of safety needles can be found in U.S. Pat. Nos. 5,401,247 and 5,637,096.
Also these safety needles have the disadvantage that they do not allow a simultaneous flow of two or more fluids throughout the different cannulas of this needle.
Known solutions that could provide multi-flow applications, such as catheters, then require several steps for insertion and still have to be inserted using a separate sharp needle which can harm an inner anatomical structure that does not need to or may not at all be penetrated.
An additional disadvantage of catheters that are made out of plastic is that they become weak when they are subjected to excessive heat.
International patent application WO 02/085444 entitled “Laparoscopic Insertion Device” describes an instrument for laparoscopic surgery that comprises an outer cannula 86 with outer cannula orifices 84, an annular wall 90 that is silver soldered to the outer cannula 86 to form a first channel for fluids, an inner cannula 88 with inner cannula orifices 94, and an obturator 38 with blunt distal tip 38 that must be removed in order to enable the inner cannula to form a second channel for fluids. In FIG. 6 of WO 02/085444, the laparoscopic insertion device is shown in a retracted position. In FIG. 4 of WO 02/085444, the laparoscopic insertion device is shown in an advanced position. A hub with spring 44 is arranged to bias the laparoscopic insertion device in the advanced position in absence of resistance.
The laparoscopic device known from WO 02/085444 is limited in use and has several disadvantages. First, it is a fairly large device with an outer diameter of 0.203 inches (see page 8, lines 14-18) or 5.16 mm which cannot be pierced through tissue. Inserting the laparoscopic device known from WO 02/085444 consequently requires an incision. The laparoscopic device known from WO 02/085444 in other words cannot be used as a needle that is pierced through tissue. Furthermore, because of the many parts, including a.o. an obturator 38, an annular wall 90, an O-ring seal 48, etc., the laparoscopic device of WO 02/085444 cannot be scaled down to obtain the diameter of a needle that can be pierced through tissue as this would reduce the effective space for fluids and consequently the achievable flow rates unacceptably.
As a result of the presence of the annular wall 90 that is silver soldered to the outer cannula 86 to form a first channel for fluids and the obturator 38, the space between the inner cannula and outer cannula is non-optimal.
In order to use the inner cannula as a second channel for fluids, the obturator must be removed during the surgery. The obturator must be unthreaded and thereafter retracted in order to be removed. Unthreading and retracting the obturator introduces a risk for damaging tissue surrounding the tip of the insertion device. While removing the obturator, the inner cannula may exercise a suction force on surrounding tissue. The inner cannula consequently cannot be used to remove fluids/gasses since there is a risk that tissue or a cavity wall becomes adhered to the tip of the inner cannula as a result of the suction force. Moreover, once the obturator is removed, internal space is in open communication with external space through the inner cannula. Fluids may escape from the inner space increasing the risk for contamination.
Consequently, there exists a need to provide a multi-cannula surgical instrument according to the preamble of the first claim allowing a simultaneous multi-flow (inflow, outflow or a combination thereof) of fluids throughout the multi-cannula surgical instrument. Such a multi-cannula surgical instrument which is designed to allow a simultaneous in- and outflow for instance can be used to flush an anatomical cavity.
A further need is to provide such a multi-purpose multi-cannula surgical instrument that is employable as an electrocautery instrument as well as a safety needle, more preferably wherein a minimum number of parts have to be altered to perform another functionality.
There further exists a need to provide such a multi-cannula surgical instrument which is easy to use and easy to manipulate during the surgical act.
In case of an electrocautery instrument, there furthermore exists a need to provide an electrocautery instrument wherein no manual manipulation is necessary to move the inner cannula within the outer cannula. The suction of fumes, fluids and debris is a function of the distance of the outer and inner cannula and the tissue. Manual manipulation is slow, cumbersome and always a compromise.
In case of a safety needle, it is furthermore a need to provide a multi-cannula surgical instrument which has the safety characteristics of a Veress needle, i.e. reducing the danger to unintentionally penetrate tissue that has not to be penetrated or that may not be penetrated. There furthermore exists a need to provide a safety needle that is applicable in a broader application field than the known Veress and safety needles. It is also a need to replace the existing catheters in areas where undesired harming of tissue is possible due to the mandatory insertion of a needle in the body to introduce the catheter into the body.